Glucose galactose malabsorption (GGM) is a rare metabolic disease caused by a defect in glucose and galactose transport across the intestinal lining. GGM is characterized severe diarrhea and dehydration as early as the first day of life and can result in rapid death if lactose, sucrose, glucose, and galactose aren't removed from the diet. At least 10% of people have glucose intolerance. However, many of those people might have a milder form of the disease.
Molecular Basis of Disease
GGM is an autosomal recessive disorder that affects individuals by inheriting two defective copies of the SGTL1 gene, located on chromosome 22. Normally within in the closed space of the small intestine (called the lumen), lactose is broken down by glucose and galactose by an enzyme called lactase, while sucrose is broken down into glucose and fructose by an enzyme called sucrase. The protein product of SGTL1 then moves the glucose and galactose from the lumen into intestinal cells. Usually the mutations carried by GGM individuals result in nonfunctional truncated SGTL1 proteins or in the improper placement of the proteins such that they can not transport glucose and galactose out of the intestinal lumen. The glucose and galactose draw water out of the body into the intestinal lumen, resulting in diarrhea.
People With GGM
Although no cure exists for GGM, patients can control their symptoms by removing lactose, sucrose, and glucose from their diets. Infants showing a prenatal diagnosis of GGM will thrive on a fructose-based replacement formula and will later continue their "normal" physical development on a fructose-based solid diet. Older children and adults with severe GGM can also manage their symptoms on a fructose-based diet and may show improved glucose tolerance and even clinical remission as they age.
Glucose Galactose Malabsorption (GGM)
Table of Contents
General Overview
Glucose galactose malabsorption (GGM) is a rare metabolic disease caused by a defect in glucose and galactose transport across the intestinal lining. GGM is characterized severe diarrhea and dehydration as early as the first day of life and can result in rapid death if lactose, sucrose, glucose, and galactose aren't removed from the diet. At least 10% of people have glucose intolerance. However, many of those people might have a milder form of the disease.Molecular Basis of Disease
GGM is an autosomal recessive disorder that affects individuals by inheriting two defective copies of the SGTL1 gene, located on chromosome 22. Normally within in the closed space of the small intestine (called the lumen), lactose is broken down by glucose and galactose by an enzyme called lactase, while sucrose is broken down into glucose and fructose by an enzyme called sucrase. The protein product of SGTL1 then moves the glucose and galactose from the lumen into intestinal cells. Usually the mutations carried by GGM individuals result in nonfunctional truncated SGTL1 proteins or in the improper placement of the proteins such that they can not transport glucose and galactose out of the intestinal lumen. The glucose and galactose draw water out of the body into the intestinal lumen, resulting in diarrhea.People With GGM
Although no cure exists for GGM, patients can control their symptoms by removing lactose, sucrose, and glucose from their diets. Infants showing a prenatal diagnosis of GGM will thrive on a fructose-based replacement formula and will later continue their "normal" physical development on a fructose-based solid diet. Older children and adults with severe GGM can also manage their symptoms on a fructose-based diet and may show improved glucose tolerance and even clinical remission as they age.References
http://www.ncbi.nlm.nih.gov/books/NBK22210/